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WO2019027012A1 - Dispositif de chauffage d'image et dispositif de formation d'image - Google Patents

Dispositif de chauffage d'image et dispositif de formation d'image Download PDF

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Publication number
WO2019027012A1
WO2019027012A1 PCT/JP2018/029100 JP2018029100W WO2019027012A1 WO 2019027012 A1 WO2019027012 A1 WO 2019027012A1 JP 2018029100 W JP2018029100 W JP 2018029100W WO 2019027012 A1 WO2019027012 A1 WO 2019027012A1
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WO
WIPO (PCT)
Prior art keywords
image
heating
recording material
fixing
heat generation
Prior art date
Application number
PCT/JP2018/029100
Other languages
English (en)
Japanese (ja)
Inventor
片岡　洋
岩崎　敦志
弘和 奥川
宗人 倉田
Original Assignee
キヤノン株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from JP2018141516A external-priority patent/JP7073220B2/ja
Application filed by キヤノン株式会社 filed Critical キヤノン株式会社
Publication of WO2019027012A1 publication Critical patent/WO2019027012A1/fr
Priority to US16/779,991 priority Critical patent/US11029627B2/en

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Classifications

    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G15/00—Apparatus for electrographic processes using a charge pattern
    • G03G15/20—Apparatus for electrographic processes using a charge pattern for fixing, e.g. by using heat
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G21/00—Arrangements not provided for by groups G03G13/00 - G03G19/00, e.g. cleaning, elimination of residual charge
    • G03G21/14—Electronic sequencing control
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B3/00—Ohmic-resistance heating

Definitions

  • the present invention relates to a fixing device mounted on an image forming apparatus such as a copier or a printer using an electrophotographic method or an electrostatic recording method, or a glossiness of a toner image by reheating a fixed toner image on a recording material.
  • an image heating apparatus such as a glossing apparatus for improving image quality.
  • the present invention also relates to an image forming apparatus provided with this image heating apparatus.
  • an image heating apparatus there is an apparatus having an endless belt (also referred to as an endless fixing film), a heater that contacts the inner surface of the endless belt and generates heat when energized, and a roller that forms a nip with the heater via the endless belt.
  • This image heating apparatus has a feature of being excellent in quick start performance and power saving performance since the heat capacity is small.
  • Patent Document 1 a configuration (Patent Document 1) has been proposed in which a toner image portion formed on a recording material is selectively heated.
  • This configuration is a divided heater in which the heat generation range of the heater is divided into a plurality of heat generation blocks (heating areas) with respect to the longitudinal direction of the heater (direction orthogonal to the conveyance direction of the recording material P).
  • the split heater selectively controls the heat generation of each heat generation block according to the presence or absence of the image on the recording material.
  • power saving is achieved by stopping energization of the heat generation block in a portion (non-image portion) where there is no image on the recording material.
  • various improvements and configurations can be made, such as reducing the heat capacity by reducing the diameter and thickness of the members, increasing the heat conductivity and insulating the members, and selectively heating only the necessary image area. Energy saving.
  • the object of the present invention is to provide a technology capable of always obtaining uniform fixing performance and stable recording material transportability throughout the life of the image heating apparatus even when the user's use conditions such as various images and recording materials are different. It is to be.
  • the image heating apparatus of the present invention is A heater having a plurality of heating elements aligned in the longitudinal direction of the substrate and the substrate provided on the substrate, a cylindrical film rotating while the inner surface is in contact with the heater, and a rotation in contact with the outer surface of the film An image for heating an image formed on the recording material using the heat of the heater while nipping and conveying the recording material at the nip portion between the film and the pressing member.
  • a heating unit An energization control unit that selectively controls energization of the plurality of heating elements so as to selectively heat the plurality of heating regions according to the information of the image;
  • An image heating apparatus comprising An acquisition unit configured to acquire an accumulated heat generation amount of the heating element in each of the plurality of heating areas, an accumulated rotation time of the pressure member, and information of a recording material passing through the nip portion;
  • the energization control unit controls energization of the plurality of heating elements based on the information acquired by the acquisition unit.
  • the image forming apparatus of the present invention is An image forming unit that forms an image on a recording material; A fixing unit that fixes an image formed on a recording material to the recording material; In an image forming apparatus having The fixing unit is the image heating device.
  • an image heating apparatus capable of obtaining stable fixing performance regardless of the use condition of the user.
  • Sectional view of an image forming apparatus according to an embodiment of the present invention Sectional view of an image heating apparatus according to an embodiment of the present invention Heater configuration diagram in the embodiment of the present invention Heater control circuit diagram in the embodiment of the present invention Figure showing the heating zone in an embodiment of the invention Explanatory drawing regarding classification of the heating area
  • Flow chart in the embodiment of the present invention Measurement of the amount of abrasion of the surface of the fixing film in the embodiment of the present invention Measurement chart of hardness change of pressure roller in the embodiment of the present invention Measurement chart of pressure roller hardness and fixing nip width in the embodiment of the present invention Measurement chart of fixing nip width and fixing control temperature in the embodiment of the present invention Explanatory drawing of verification of the effect in the Example of this invention.
  • FIG. 1 is a schematic cross-sectional view of an image forming apparatus according to an embodiment of the present invention.
  • the image forming apparatus 100 of this embodiment is a laser beam printer that forms an image on a recording material using an electrophotographic method.
  • the scanner unit 21 emits a laser beam modulated according to the image information, and the charging roller 16 scans the surface of the photosensitive drum (electrophotographic photosensitive member) 19 charged to a predetermined polarity.
  • an electrostatic latent image is formed on the photosensitive drum 19 as an image carrier.
  • the electrostatic latent image on the photosensitive drum 19 is developed as a toner image (developer image).
  • the recording material P stacked on the sheet feeding cassette 11 is fed sheet by sheet by the pickup roller 12 and is conveyed by the conveyance roller pair 13 toward the registration roller pair 14.
  • the recording material P is conveyed from the registration roller pair 14 to the transfer position in synchronization with the timing when the toner image on the photosensitive drum 19 reaches the transfer position formed by the photosensitive drum 19 and the transfer roller 20.
  • the toner image on the photosensitive drum 19 is transferred to the recording material P while the recording material P passes through the transfer position.
  • the recording material P is heated and pressed by a fixing device (image heating device) 200 as a fixing portion (image heating portion), and the toner image is heat-fixed on the recording material P.
  • the recording material P carrying the fixed toner image is discharged to a tray at the upper portion of the image forming apparatus 100 by the conveyance roller pairs 26 and 27.
  • the paper feed tray (manual feed tray) 28 has a pair of recording paper regulating plates whose width can be adjusted according to the size of the recording paper P, and is provided to cope with recording paper P of sizes other than the standard size. It is done.
  • the pickup roller 29 is a roller for feeding the recording sheet P from the sheet feeding tray 28.
  • the motor 30 drives the fixing device 200 and the like. Electric power is supplied to the fixing device 200 from a control circuit 400 as an energization control unit and an acquisition unit connected to a commercial AC power supply 401.
  • the photosensitive drum 19, the charging roller 16, the scanner unit 21, the developing roller 17, and the transfer roller 20 described above constitute an image forming unit for forming an unfixed image on the recording material P. Further, in the present embodiment, a developing unit including the photosensitive drum 19, the charging roller 16, and the developing roller 17, and a cleaning unit including the drum cleaner 18 are detachably configured as the process cartridge 15 with respect to the apparatus main body of the image forming apparatus 100. It is done.
  • the maximum sheet passing width in the direction orthogonal to the conveyance direction of the recording material P is 216 mm and plain paper of A4 size [210 mm ⁇ 297 mm] is conveyed at a conveyance speed of 232.5 mm / sec. It is possible to print 41.9 minutes.
  • FIG. 2 is a cross-sectional view of a fixing device 200 as an image heating device of the present embodiment.
  • the fixing device 200 includes a fixing film 202, a heater 300 in contact with the inner surface of the fixing film 202, a pressure roller 208 forming the fixing nip N with the heater 300 via the fixing film 202, and a metal stay 204.
  • the fixing film 202 is a high heat resistant fixing film having a multilayer structure formed in a cylindrical shape, which is also referred to as an endless belt or an endless film, and uses a heat resistant resin such as polyimide or a metal such as stainless steel as a base layer.
  • the surface of the fixing film 202 is a release layer coated with a high-performance fluorocarbon resin excellent in heat release property and excellent in releasability such as PFA for preventing adhesion of toner.
  • a high-performance fluorocarbon resin excellent in heat release property and excellent in releasability such as PFA for preventing adhesion of toner.
  • high heat resistant rubber such as silicone rubber may be formed as an elastic layer between the base layer and the release layer in order to improve the image quality.
  • the pressure roller 208 is configured to have a core metal 209 made of iron, aluminum or the like and an elastic layer 210 made of high heat resistant rubber such as silicone rubber.
  • the fixing nip N corresponding to the fixing device 200 is obtained by using the pressure roller 208 having such a configuration and having an appropriate hardness.
  • the heater 300 is held by a heater holding member 201 made of a heat-resistant resin, and heats the fixing film 202 by heating the heating areas A 1 to A 7 (details will be described later) in the fixing nip portion N.
  • the heater holding member 201 also has a guide function of guiding the rotation of the fixing film 202.
  • an electrode E is provided on the opposite side of the fixing nip N, and power is supplied to the electrode E from an electrical contact C.
  • the metal stay 204 receives a pressure (not shown) to press the heater holding member 201 toward the pressure roller 208.
  • a safety element 212 such as a thermo switch or a thermal fuse that operates by abnormal heat generation of the heater 300 to shut off the power supplied to the heater 300 abuts the heater 300 directly or indirectly via the heater holding member 201. ing.
  • the pressure roller 208 receives the rotational driving force from the motor 30 and rotates in the direction of the arrow R1. As the pressure roller 208 rotates, the fixing film 202 whose outer surface is in contact with the pressure roller 208 is driven to rotate in the direction of arrow R2.
  • the unfixed toner image on the recording material P is subjected to a fixing process by applying heat from the heat generating member disposed on the substrate of the heater 300 through the fixing film 202 while holding and conveying the recording material P at the fixing nip N. Ru.
  • a sliding grease (not shown) having high heat resistance is interposed between the heater 300 and the fixing film 202. .
  • FIG. 3A is a cross-sectional view of the heater 300
  • FIG. 3B is a plan view of each layer of the heater 300
  • FIG. 3C is a view for explaining a method of connecting the electrical contact C to the heater 300.
  • FIG. 3B shows the conveyance reference position X of the recording material P in the image forming apparatus 100 of the present embodiment.
  • the conveyance reference is the center reference
  • the recording material P is conveyed such that the center line in the direction orthogonal to the conveyance direction is along the conveyance reference position X.
  • 3A is a cross-sectional view of the heater 300 at the conveyance reference position X.
  • the heater 300 is provided on the ceramic substrate 305, the back surface layer 1 provided on the substrate 305, the back surface layer 2 covering the back surface layer 1, and the surface on the substrate 305 opposite to the back surface layer 1.
  • a sliding surface layer 1 and a sliding surface layer 2 covering the sliding surface layer 1 are provided.
  • the back surface layer 1 has a conductor 301 (301a, 301b) provided along the longitudinal direction of the heater 300.
  • the conductor 301 is separated into a conductor 301a and a conductor 301b, and the conductor 301b is disposed downstream of the conductor 301a in the conveyance direction of the recording material P.
  • the back surface layer 1 also has conductors 303 (303-1 to 303-7) provided in parallel to the conductors 301a and 301b.
  • the conductor 303 is provided along the longitudinal direction of the heater 300 between the conductor 301 a and the conductor 301 b.
  • the back surface layer 1 further includes a heating element (heating resistor) 302a (302a-1 to 302a-7) and a heating element 302b (302b-1 to 302b-7).
  • the heating element 302 a is provided between the conductor 301 a and the conductor 303, and generates heat by supplying power through the conductor 301 a and the conductor 303.
  • the heating element 302 b is provided between the conductor 301 b and the conductor 303, and generates heat by supplying power through the conductor 301 b and the conductor 303.
  • a heat generating portion composed of the conductor 301, the conductor 303, the heating element 302a and the heating element 302b is divided into seven heating blocks (HB 1 to HB 7 ) in the longitudinal direction of the heater 300. That is, the heating element 302 a is divided into seven regions of the heating elements 302 a-1 to 302 a-7 in the longitudinal direction of the heater 300. The heating element 302 b is divided into seven regions of the heating elements 302 b-1 to 302 b-7 in the longitudinal direction of the heater 300. Further, the conductor 303 is divided into seven regions of conductors 303-1 to 303-7 in accordance with the division positions of the heating elements 302a and 302b.
  • Heating range of this embodiment is in the range from left end in the drawing of the heating blocks HB 1 to right end in the drawing of the heating block HB 7, its length is 220 mm. Moreover, although the longitudinal direction length of each heat generating block is all the same about 31 mm, you may make length different.
  • the back layer 1 has electrodes E (E 1 to E 7 and E 8-1 , E 8-2 ).
  • the electrodes E 1 to E 7 are provided in the regions of the conductors 303-1 to 303-7, respectively, and power is supplied to the heating blocks HB 1 to HB 7 through the conductors 303-1 to 303-7, respectively. It is an electrode for The electrodes E 8-1 and E 8-2 are provided at the longitudinal end of the heater 300 so as to be connected to the conductor 301, and supply power to the heat generating blocks HB 1 to HB 7 through the conductor 301.
  • the electrodes E 8-1 and E 8-2 are provided at both ends in the longitudinal direction of the heater 300, but for example, only the electrode E 8-1 may be provided on one side.
  • power is supplied to the conductors 301a and 301b using a common electrode, separate electrodes may be provided on the conductors 301a and 301b to supply power.
  • the back surface layer 2 is composed of an insulating surface protection layer 307 (glass in this embodiment), and covers the conductor 301, the conductor 303, and the heating elements 302a and 302b. Further, the surface protective layer 307 is formed except for the portion of the electrode E (so that the electrode E is exposed), and the electric contact C can be connected to the electrode E from the back surface layer 2 side of the heater 300.
  • the configuration is as follows.
  • the sliding surface layer 1 has thermistors TH (TH1-1 to TH1-4 and TH2-5 to TH2-7) for detecting the temperatures of the heat generating blocks HB1 to HB7.
  • the thermistor TH is made of a material having a PTC characteristic or an NTC characteristic (NTC characteristic in this embodiment), and by detecting the resistance value, the temperature of all the heat generation blocks can be detected.
  • the sliding surface layer 1 also conducts current to the thermistor to detect its resistance value, so that the conductors ET (ET1-1 to ET1-4 and ET2-5 to ET2-7) and the conductors EG (EG1, EG2) And.
  • Conductors ET1-1 to ET1-4 are connected to thermistors TH1-1 to TH1-4, respectively.
  • the conductors ET2-5 to ET2-7 are connected to thermistors TH2-5 to TH2-7, respectively.
  • the conductor EG1 is connected to the four thermistors TH1-1 to TH1-4 to form a common conduction path.
  • the conductor EG2 is connected to the three thermistors TH2-5 to TH2-7 to form a common conduction path.
  • Conductor ET and conductor EG are formed along the longitudinal direction of heater 300 to the longitudinal end, and are connected to control circuit 400 at the longitudinal end of heater 300 via electrical contacts (not shown).
  • the sliding surface layer 2 is composed of a surface protection layer 308 having sliding properties and insulating properties (glass in this embodiment), and covers the thermistor TH, the conductor ET and the conductor EG, and the inner surface of the fixing film 202 It secures the slidability with the Further, the surface protective layer 308 is formed except for both longitudinal ends of the heater 300 in order to provide electrical contacts to the conductor ET and the conductor EG.
  • FIG. 3C is a plan view of the state in which the electrical contacts C are connected to the electrodes E as viewed from the heater holding member 201 side.
  • the heater holding member 201 is provided with a through hole at a position corresponding to the electrodes E (E 1 to E 7 and E 8-1 and E 8-2 ).
  • electrical contacts C (C 1 -C 7 and C 8-1 , C 8-2 ) are connected to electrodes E (E 1 -E 7 and E 8-1 , E 8-2 )
  • they are electrically connected by a method such as biasing by springs or welding.
  • the electrical contact C is connected to a control circuit 400 of the heater 300 described later via a conductive material (not shown) provided between the metal stay 204 and the heater holding member 201.
  • FIG. 4 is a circuit diagram of a control circuit 400 of the heater 300 according to the first embodiment.
  • a commercial AC power supply 401 is connected to the image forming apparatus 100. Power control of the heater 300 is performed by turning on / off the TRIAC 411 to the TRIAC 417.
  • the triacs 411 to 417 operate in accordance with the FUSER1 to FUSER7 signals from the CPU 420, respectively.
  • the drive circuits of the triacs 411 to 417 are omitted.
  • the control circuit 400 of the heater 300 has a circuit configuration capable of individually controlling the seven heat generating blocks HB 1 to HB 7 divided in the longitudinal direction independently by selectively controlling the seven triacs 411 to 417. ing.
  • the zero cross detection unit 421 is a circuit that detects the zero cross of the AC power supply 401, and outputs a zero cross signal to the CPU 420.
  • the zero cross signal is used for phase control of the TRIACs 411 to 417, detection of the timing of wave number control, and the like.
  • a method of detecting the temperature of the heater 300 will be described.
  • the temperature detection of the heater 300 is performed by thermistors TH (TH1-1 to TH1-4, TH2-5 to TH2-7) as temperature detection elements constituting the temperature detection unit.
  • the partial pressure between the thermistors TH1-1 to TH1-4 and the resistors 451 to 454 is detected by the CPU 420 as TH1-1 to TH1-4 signals, and the CPU 420 sets the TH1-1 to TH1-4 signals as temperatures. It is converting.
  • the partial pressure of the thermistors TH2-5 to TH2-7 and the resistors 465 to 467 is detected by the CPU 420 as TH2-5 to TH2-7 signals, and the CPU 420 detects TH2-5 to TH2-7.
  • the signal is converted to temperature.
  • the power to be supplied is calculated based on, for example, PI control (proportional integration control) based on the control temperature (control target temperature) TGTi of each heat generation block described later and the detected temperature of the thermistor. Furthermore, the power supplied is converted to a control level of phase angle (phase control) corresponding to the power or a wave number (wave number control), and the TRIACs 411 to 417 are controlled according to the control condition.
  • PI control proportional integration control
  • TGTi control target temperature
  • wave number control wave number control
  • the circuit operation of the relay 430 will be described.
  • the CPU 420 sets the RLON signal to the high state, the transistor 433 as a drive element is turned on, and the power supply voltage Vcc energizes the secondary coil of the relay 430, and the primary contact of the relay 430 is turned on.
  • the RLON signal is in the low state, the transistor 433 is turned off, the current flowing from the power supply voltage Vcc to the secondary coil of the relay 430 is cut off, and the primary contact of the relay 430 is turned off.
  • the operation of the relay 440 is similar. Note that resistors 434 and 444 limit the base current of the transistors 433 and 443.
  • the relay 430 and the relay 440 are used as a means for interrupting power to the heater 300 to ensure safety.
  • the operation of the safety circuit (power cut-off unit) using the relay 430 and the relay 440 (cut-off operation to cut off the power supply to the heating element) will be described.
  • the relay 430 is turned off to ensure safety.
  • the comparison unit 431 operates the latch unit (latch circuit) 432, and the latch unit 432 latches the RLOFF1 signal in the low state.
  • the transistor 433 When the RLOFF1 signal is in the low state, the transistor 433 is maintained in the OFF state even when the CPU 420 sets the RLON signal in the high state, so that the relay 430 can be maintained in the OFF state (safe state).
  • the comparison unit 441 operates the latch unit 442 to latch the RLOFF2 signal in the low state and latch it. , And the relay 440 is in a non-conductive state to ensure safety.
  • Heating Area FIG. 5 is a view showing the heating areas A 1 to A 7 in the present embodiment, and is shown in contrast to the recording material width of A4 size.
  • the recording material P passing through the fixing nip N is divided into sections at a predetermined time, and the heating area Ai is classified for each section.
  • division into sections is provided every 0.3 seconds on the basis of the leading edge of the recording material P as shown in FIG. 6A, the first section is section T 1 , and the second section is section T Let the second and third intervals be intervals T 3 and so on.
  • the size of the recording material P, a size of its ends passes through the heating area A 2 and the heating area A 6, and if the image is present in the position shown in FIG. 6 (A), the heating area A i
  • the classification is as shown in the table of FIG. 6 (B).
  • the heating region A 1, A 7 is classified to the recording material P does not pass the non-paper passing heated area AN (Non Paper Area).
  • the heating areas A 2 , A 3 and A 4 are classified into the image heating area AI (Image Area) because the image area passes, and the heating areas A 5 and A 6 are the non-image heating area because the image area does not pass. It is classified into AP (Paper Area).
  • the heating areas A 1 and A 7 are for the non-sheet heating area AN
  • the heating areas A 2 , A 3 and A 6 are for the non-image heating area AP
  • the heating areas A 4 and A 5 are respectively classified into the image heating area AI.
  • the heating region A 1, A 7 is in the non-paper passing the heating region AN
  • heating area A 2 ⁇ 6 are classified respectively in the non-image heating area AP.
  • the fixing member When the fixing member responsible for heat transfer frictionally slides in a high temperature state, wear occurs on the sliding surface, and the heat conductivity changes depending on the degree of wear. Due to this change, the fixing performance may not be stable throughout the life.
  • a fixing film surface layer as a fixing member, one coated with a fluorine resin is widely and generally used to prevent adhesion of toner.
  • fluorine resin such as PFA (tetrafluoroethylene-perfluoroalkylvinylether copolymer) or PTFE (polytetrafluoroethylene), which is a high heat resistant resin having excellent releasability.
  • the high temperature offset is a phenomenon that occurs because the toner on the recording material is excessively melted due to excessive supply of heat.
  • the excessively melted toner has a reduced viscosity, and when the recording material is separated from the fixing film, it is separated (separately separated) in the toner layer, and the toner remains on the fixing film.
  • the toner remaining on the fixing film is fixed on the recording material after one rotation of the fixing film, which may cause stains on the recording material. Curl is also generated due to excessive supply of heat to the recording material at the fixing nip.
  • the pressure roller which is a pressure member, repeats expansion and cooling by heating and contraction by cooling.
  • the tension applied to the PFA resin layer that forms the surface layer of the pressure roller is reduced due to the stress applied by repeated deformation when passing through the fixing nip.
  • the silicone rubber forming the elastic layer is deteriorated and the elasticity is lowered, the hardness of the pressure roller is lowered.
  • the hardness of the pressure roller decreases, the width of the fixing nip formed by applying a predetermined pressure between the fixing film and the pressure roller increases, and the time for the recording material to pass through the fixing nip increases, and the recording material Heating time to will be longer. As a result, the amount of heat supplied to the recording material and the toner increases, and a problem such as high temperature offset and curling occurs.
  • the corresponding technology for changing the condition of fixing execution according to the use condition of the image heating apparatus has been considered conventionally .
  • the conditions such as the fixing control temperature are changed with a predetermined number of sheets.
  • the amount of heat generation differs for each heat generation block because it responds to various image information. Therefore, the surface layer wear of the fixing film described above will be different for each heating block.
  • the uniformity of the fixing performance (fixability and glossiness) in the longitudinal direction orthogonal to the conveyance direction of the recording material is impaired, or the conveyance of the recording material becomes unstable.
  • PI control proportional integration control
  • the control temperature TGT i of each heat generation block is set according to the classification of the heating area A i determined by the flowchart of FIG. 7.
  • Classification of the heating area A i includes an image data sent from an external device such as a host computer (not shown) (image information) is performed based on the size information of the recording material P. That determines the passage of the recording material P of the heating area A i (S1002), if not pass classifies the heating area A i in the non-paper passing heated area AN (S1006).
  • the heating area A i is the recording material P passes determines whether the image range heating region A i passes (S1003), when passing through the classification the heating area A i and the image heating area AI (S1004) if not pass classifies the heating area a i and the non-image heating area AP (S1005).
  • TGT i T AI -TAF i -TAR (S1007).
  • T AI is a reference temperature of the image heating area, and is set as an appropriate temperature for fixing the unfixed toner image on the recording material P.
  • TAR is a correction term (Accumulation Rotation Time Information Revision) of accumulated rotation time information of the fixing device 200.
  • the reference temperature T AI is set to 220 ° C. It is desirable that the reference temperature T AI be suitable for the use conditions of the user. As the use conditions, information of the recording material P such as the thickness (thick, thin, etc.) and surface property (smooth, rough, etc.) as the size and type of the recording material P, and the use mode of the user such as the paper passing mode and environment It is desirable to adjust according to the information. In order to obtain information on the recording material P, the user is requested to input information from the operation unit (not shown) of the image forming apparatus 100, or a recording material type determination member (provided in the recording material P conveyance path of the image forming apparatus 100) Not shown) etc. Further, the reference temperature T AI may be adjusted in accordance with image information such as the image density, the pixel density, and the image arrangement.
  • image information such as the image density, the pixel density, and the image arrangement.
  • the correction term TAF i is a correction value of the fixing control temperature according to the accumulated heat generation amount of each heating block H i i located in each heating area A i , and the wear amount of the surface layer of the fixing film 202 is corrected as a temperature Is adopted as
  • the cumulative heat generation amount of each heat generation block HB i is defined as the product of the fixing control temperature and the time when fixing is performed, and the cumulative heat generation amount is added up as the cumulative heat generation count value CAFi (S1010) .
  • the correction term TAF i is calculated based on the count value CAFi (S1011). Detailed calculation of the count value CAFi and the correction term TAF i will be described later.
  • the correction term TAR is a correction value of the fixing control temperature according to the cumulative rotation time of the fixing device 200, and is adopted as a correction of the change of the hardness of the pressure roller 208.
  • the cumulative rotation time is added up as the cumulative rotation time Tsum (S1012).
  • the correction term TAR is calculated based on this time Tsum (S1013). Detailed calculation of the time Tsum and the correction term TAR will be described later.
  • T AP is a reference temperature of the non-image heating area, and by setting it as a temperature lower than the reference temperature T AI , the calorific value of the heat generation block HB i in the non-image heating area AP is lowered than that of the image heating area AI Power saving of the image forming apparatus 100 is achieved.
  • the reference temperature TAP 162 ° C.
  • Count CAFi computation time Tsum, correction term TAF i, the calculation of the correction term TAR, a previous heating area A i is the image heating area AI (S1004) if the same steps (S1014 ⁇ S1017).
  • T AN is the reference temperature in the non-paper feed heating zone, by setting a temperature lower than the reference temperature T AP, the heating value of the heating block HB i in the non-paper passing the heating region AN lower than the non-image heating area AP, Power saving of the fixing device 200 is achieved.
  • the conveyance of the recording material P can be stabilized by setting the reference temperature T AN to 128 ° C. or more in the fixing device 200 of the present embodiment.
  • T AP 128 ° C.
  • the reference temperature T AN should be determined in consideration of the configuration of the fixing device 200 including the viscosity characteristics of the grease, and is not limited to 128 ° C.
  • the surface layer of the fixing film 202 is abraded by the passage of the recording material P. The reason is that the difference in speed between the recording material P and the fixing film 202 is extremely small.
  • the pressure roller 208 transports the recording material P by the rotation of the pressure roller 208, and the friction between the recording material P and the fixing film 202 causes the fixing film 202 to It is configured to be driven to rotate.
  • the surface of the fixing film 202 is formed of a fluorine resin such as PFA or PTFE in order to obtain releasability, so the coefficient of friction is low.
  • the peripheral speed of the fixing film 202 is slightly smaller than the conveyance speed of the recording material P, but is slower.
  • the recording material P contains an inorganic material such as calcium carbonate or kaolin as a filler for making the recording material P itself white and opaque. These fillers act as an abrasive on the surface layer of the fixing film 202 and scrape the surface layer of the fixing film 202.
  • the speed at which the surface of the fixing film 202 wears is related to the surface temperature of the fixing film 202 and the time during which the temperature is applied.
  • fluorine resins such as PFA and PTFE are also softened and deformed by elastic deformation due to external stress and heating. If the temperature of the fixing film 202 rises and the temperature of the fixing film 202 is increased and the fluororesin is softened, it is considered that the filler of the recording material P bites deeper into the fixing film 202 when the fixing film N is pressed. In this state, the fixing film 202 and the recording material P are considered to be abraded due to a slight difference in speed, although they are very slight.
  • FIG. 8 shows the result of confirmation of wear by changing the temperature of the fluorine resin layer on the surface of the fixing film 202 by changing the fixing control temperature of the fixing device 200 in order to know the influence of the wear of the fluorine resin due to the temperature.
  • the horizontal axis represents the surface temperature [° C.] of the fixing film 202
  • the vertical axis represents the A4 size recording material P having a basis weight of 80 [g / m 2 ] when 1000 sheets (1K [sheets]) are passed.
  • the amount of wear [ ⁇ m] is shown. It can be seen that the amount of wear increases as the surface temperature of the fixing film 202 increases.
  • the surface layer wear of the fixing film 202 is greatly influenced by the surface temperature of the fixing film and the timing at which the fixing film 202 rubs against the recording material P, that is, the time when the recording material P passes through the fixing nip N. . Therefore, in the present embodiment, as a parameter for estimating the surface layer wear of the fixing film 202, the product of the fixing control temperature determining the surface temperature of the fixing film 202 and the passing time is defined.
  • the optimum fixing performance can be obtained by maintaining the surface temperature of the fixing film 202 at about 180.degree.
  • the surface film thickness of the fixing film 202 in the unused state of the present embodiment is set to 25 [ ⁇ m], and the fixing control temperature at which the surface temperature is 180 [° C.] is 220 [° C.]. It is obtained. Therefore, as described above, the reference temperature T AI is 220 ° C.
  • the fixing control temperature is set such that reliable fixing performance can be obtained even when the fixing property becomes severe due to the variation of parts generated during production of the fixing device 200, the use condition, and the like. . That is, the reference temperature T AI 220 [° C.] is determined in consideration of the condition that the fixability becomes severe.
  • the surface temperature of the fixing film 202 becomes high. Curling will occur.
  • the surface temperature of the fixing film 202 is 180 [° C. even if the surface layer of the fixing film 202 is worn and becomes thin. It is necessary to maintain Therefore, in the first embodiment of the present invention, it is assumed in accordance with the surface layer thickness of the fixing film 202 facing the fixing control temperature of the heating block each HB i to the heating block HB i. Accordingly, it is an object of the present invention to always obtain optimum fixing performance.
  • the fixing control temperature TGT i at the time of executing fixing and the passing time of the recording material P are stored in the non-volatile memory 410 (see FIG. 1) as a storage unit (storage unit), and sequentially calculated and updated By doing this, the film thickness of the fixing film 202 is estimated by calculation.
  • the non-volatile memory 410 may be provided in at least one of the image forming apparatus 100 and the fixing device 200.
  • the relationship between the count value CAFi and the correction term TAF i will be described later.
  • the fixing device 200 of this embodiment uses a heater 300 having a plurality of heating elements divided in the longitudinal direction of the heater. Therefore, the count value CAFi, by and request for each of the heating blocks HB i, it is assumed that independently controlled as a fixing control temperature TGT i of each of the heating blocks HB i.
  • count value CAFi in the case where a pattern having an image on the entire surface is formed on A4 size recording material P is calculated.
  • Heating area A i is the image heating area AI next because there is an image on the entire surface
  • the reference temperature is a reference temperature T AI.
  • the control unit (not shown) of the image forming apparatus 100 is controlled by 16 bits, in order to store the count value CAFi in 16 bits, the value obtained by the above calculation is divided by 1000 and the value rounded up is used as the count value CAFi. There is. Therefore, it is calculated as 1 by rounding up 0.2816 obtained by dividing 281.6 by 1000.
  • Such calculation of the cumulative heat generation count value CAFi is calculated and updated every time fixing is performed through the use of the fixing device 200.
  • the control temperature is TGT i .
  • the pressure roller 208 which is the basis of the calculation of the correction term TAR will be described. Since the pressure roller 208 is pressed with a constant pressure against the heater 300 via the fixing film 202, the width of the fixing nip N becomes larger as the hardness is smaller (softer). When the width of the fixing nip N is increased, the time for which the recording material P passes through the fixing nip N becomes long, the amount of heat transferred from the fixing film 202 to the recording material P and the toner increases, and the toner can be melted more. On the other hand, when the hardness is high (hard), the width of the fixing nip N becomes thin.
  • the hardness of the pressure roller 208 becomes small (soft) by variation in hardness (tolerance) that occurs when producing the pressure roller 208, and by repeatedly performing fixing. In consideration of the range of change in hardness, it is necessary to set such that reliable fixing performance can be obtained at the upper and lower limits of the hardness tolerance standard.
  • the hardness change of the pressure roller 208 will be described.
  • the hardness of the pressure roller 208 is obtained by the elasticity of the silicone rubber forming the elastic layer 210 and the tension of the fluorine resin layer forming the surface layer.
  • the change in hardness occurs when the pressure roller 208, which has been heated to perform fixing, receives a load for conveying the recording material P while repeatedly forming the fixing nip N.
  • FIG. 9 shows the change in hardness of the pressure roller 208 as a result of sheet passing.
  • the horizontal axis of the graph is the rotational driving time of the pressure roller 208 by sheet passing, and it takes about 40 [hours] to pass about 50000 [sheets].
  • the vertical axis shows the hardness change [°].
  • the change in hardness of the pressure roller 208 is large immediately after the start of use from the new state (section a), but becomes smaller after sheet passing (section b). This tendency is due to the following.
  • the pressure roller 208 transports the recording material P, so the outer diameter of the pressure roller 208 affects the transport speed of the recording material P.
  • the conveyance speed of the recording material P is increased.
  • the conveyance speed of the recording material P is increased. Will be late.
  • the recording material P present in the fixing nip N is a transfer nip consisting of the photosensitive drum 19 and the transfer roller 20 as a roller pair on the upstream side of the fixing nip N, and a roller pair on the downstream side.
  • the sheet is also nipped and conveyed by the discharge roller pair 26.
  • the roller pair that has the largest influence on the conveyance of the recording material P is the fixing nip N with the largest pressure. Therefore, it is desirable that the variation (swing) of the transport speed at the fixing nip N be as small as possible, and the outer diameter tolerance of the pressure roller 208 is required to be as small as possible in the mass production. Therefore, in order to make the outer diameter tolerance small and stable, at the stage of manufacturing the pressure roller 208, a PFA tube having an inner diameter smaller than the outer diameter of the elastic layer 210 is coated on the elastic layer 210, and the elastic layer 210 is formed by the PFA tube. It has a configuration to tighten.
  • the elastic layer 210 is a layer of silicone rubber having a linear expansion coefficient of 250 to 450 [10 ⁇ 6 / K] and having a thickness of 2.5 [mm], and therefore, expands as the temperature rises.
  • the PFA resin layer which is a fluorine resin layer as a release layer, has a linear expansion coefficient of 100 to 120 [10 ⁇ 6 / K], which is smaller than that of silicone, and a film thickness of 50 ⁇ m. For this reason, when the silicone rubber elastic layer 210 expands, the PFA resin layer is stretched. After the fixing is performed, when the fixing device 200 cools, the silicone rubber elastic layer 210 which has expanded due to the temperature rise is contracted due to the compression set which is the characteristic of the rubber.
  • the stretched PFA resin layer has a plastic deformation which is a characteristic of the resin, so that the shrinkage change becomes small, and the stretched PFA resin layer remains in the stretched state.
  • the tension of the PFA resin layer becomes small. Therefore, the pressure roller hardness obtained by the tension of the PFA resin layer when the pressure roller is new is lowered. This decrease in hardness occurs largely at the beginning as shown by section a in FIG.
  • the subsequent hardness change is due to the thermal stress caused by the temperature increase of the pressure roller 208 and the deterioration of the silicone rubber due to the deformation and load caused by repeatedly forming the fixing nip N and conveying the recording material P. .
  • the change in hardness is smaller than the decrease in hardness due to the initial tension reduction, and changes like a slow section b.
  • FIG. 10 shows the result of confirming the relationship between the hardness of the pressure roller 208 and the width of the fixing nip N in this embodiment.
  • the horizontal axis of the graph is the pressure roller hardness [°]
  • the vertical axis is the width [mm] of the fixing nip N. It can be seen that the width of the fixing nip N is increased by 0.4 [mm] when the pressure roller hardness decreases by 2 [°].
  • FIG. 11 shows the results of confirmation of the width of the fixing nip N and the fixing control temperature.
  • the horizontal axis of the graph is the width [mm] of the fixing nip N
  • the vertical axis is the fixing control temperature [° C.] at which the optimum fixing performance is obtained.
  • time Tsum accumulation of the rotation time of the pressure roller 208 according to the execution of fixing is calculated as time Tsum, stored in the non-volatile memory 410, and calculated and updated sequentially.
  • the correction term TAR is corrected as the fixing control temperature TGT i according to the change in width of the fixing nip N.
  • Time Tsum is the same time in the longitudinal of the pressure roller 208, not able in this embodiment to divide the correction term TAR each heating block HB i. However, the correction term TAR i may be calculated for each heating block HB i .
  • the time Tsum is defined as the time when the pressure roller 208 is rotationally driven.
  • the image forming apparatus 100 and the fixing device 200 used in the present embodiment have the following steps.
  • Pre-rotation A preparation step of an image forming process for stabilizing the potential of the photosensitive drum 19 and stabilizing the rotation of the laser scanner 21, an image formed on the photosensitive drum 19, and an image on the photosensitive drum 19 transferred
  • a step of conveying the recording material P to the image heating apparatus 100 is included. During this process, the process of raising the temperature of the fixing film 202 and the pressure roller 208 is also included.
  • Passage In this process, the recording material P carrying the unfixed toner is passed through the fixing nip N for fixing.
  • Paper interval This is a process during conveyance of the recording material P and the next recording material P when continuous sheet passing is performed.
  • Post-rotation A step of discharging the recording material P out of the apparatus and shifting the image forming apparatus 100 to the standby state.
  • the required time in each process is as follows. Previous rotation: 4.3 [seconds] Paper passing: 1.28 [seconds] (A4 size 297 [mm]) Paper interval: 0.145 [seconds] Post-rotation: 0.97 [seconds]
  • the time Tsum obtained as the time when the fixing device 200 rotationally drives including the above-described processes is used as the correction term TAR of the cumulative rotation time information shown in Table 2. Since the hardness drop of the pressure roller 208 is large at the initial stage of a new product, the correction of the fixing control temperature TGT i in the correction term TAR by the time Tsum is made large at the beginning of the start of use of the fixing device 200. (Table 2)
  • the fixing control temperature TGT i which is optimum for the state of the fixing device 200 according to the use condition of the user. As this, each heat generation block HB i is controlled.
  • the fixing control temperature TGT i is corrected as follows when the fixing device 200 is used, the count value of accumulated heat generation CAFi is 22000, and the accumulated rotation time Tsum is 32 hours.
  • the correction of the fixing control temperature TGT i will be described in the case where the image pattern shown in FIG.
  • the sections T 1 to T 3 of the heating area A 2 to A 5 parts are classified into the image heating area AI where the toner image is located, and are controlled at a temperature of 220 ° C. as the reference temperature T AI .
  • the heating areas A 1 , A 6 , and the sections T 1 to T 5 of 7 parts of A 7 and the sections T 4 to T 5 of A 2 to A 5 are classified into non-image heating areas AP without toner image. It is controlled at 162 [° C.] as AP .
  • CAF i reference temperature T AI * required time of section T i + reference temperature T AP * from the required time interval T i
  • the correction term TAF i is a correction of ⁇ 2 ° C.
  • the correction term TAF i is a correction of ⁇ 2 ° C.
  • the image heating region AI fixing control temperature TGT i have the image in the heating area A i is increased, a larger correction to lower the fixing control temperature TGT i, the optimum in consideration of the surface wear of the fixing film 202 Correction.
  • the correction term TAR associated with the change in hardness of the pressure roller 208 is corrected to -1 [° C.] after 575 sheets.
  • the correction term TAR after 1149 sheets is a correction of -2 ° C.
  • the correction term TAR after 9192 sheets is a correction of -3 ° C.
  • the final correction correction term TAR is obtained after the 455958 sheets, and the correction is -4 [° C.].
  • Table 3 shows the above. (Table 3)
  • correction term TAF i the correction term TAR both correction is no fixing control temperature
  • TGT i a reference temperature corresponding to the presence or absence of each of the heating blocks HB i of the image.
  • the correction term TAR is a correction of ⁇ 1 [° C.]
  • the fixing control temperature TGT i reference temperature ⁇ 1 [° C.].
  • the correction term TAR is a correction of ⁇ 2 ° C.
  • the fixing control temperature TGT i reference temperature ⁇ 2 ° C.
  • the correction term TAR is a correction of -3 [° C.]
  • correction terms TAF i and correction terms TAR are obtained by continuously passing three sheets of the image pattern shown in FIG. 12A onto the A4 size recording material P and repeating the standby state.
  • Correction Term TAF The i correction term TAR changes depending on the image pattern, the size of the recording material P, the condition of sheet passing, and the like.
  • the correction term TAF i and the correction term TAR are corrected according to the change of the fixing film 202 and the pressure roller 208.
  • the correction may be performed by only one of them.
  • the surface layer abrasion amount of the fixing film 202 corresponding to the heating areas A 2 , A 3 , A 4 and A 5 increases, and corresponds to the heating areas A 1 , A 6 and A 7 .
  • the surface wear decreases.
  • FIG. 13 shows the result of measuring the surface layer wear amount of the fixing film 202.
  • the horizontal axis of the graph indicates the heating area A i (heating block HB i).
  • the vertical axis represents the surface film thickness of the fixing film 202 at the 50000 sheet passing time, and indicates that the larger the numerical value, the smaller the surface layer wear.
  • heating the heating area A 2 ⁇ 5 the fixing control temperature TGT i have images were highly controlled area A i it is found that the surface layer wear often.
  • the PFA resin layer of the surface layer of the fixing film 202 located in the heat generation block HB i (multiple) whose accumulated heat generation amount is large becomes thin.
  • the PFA resin layer of the fixing film 202 surface layer located in the heat generation block HB i (small) having a small accumulated heat generation amount is thicker than the PFA resin layer of the fixing film 202 surface layer located in the heat generation block HB i (multiple) .
  • Table 4 shows the measurement results of the hardness of the pressure roller 208 and the width of the fixing nip N accompanying sheet passing.
  • the hardness is a value measured by an Asker-C hardness tester (weight of 9.8 N, taken as an average value of 12 measurement values obtained by measuring 3 points in the longitudinal direction and 4 points in the circumferential direction of the pressure roller 208). (Table 4)
  • the heating areas A 1 to A 7 of the section T 1 are controlled by the fixing control temperature TGT i with respect to the image heating area reference temperature, and the subsequent sections T 2 to T 5 are The fixing control temperature TGT i is controlled based on the reference temperature of the non-image heating area. (Table 5)
  • the comparative example is controlled by the same fixing control temperature TGT i regardless of the heat generation block HB i , the heating areas A 1 , A 6 , A 7 and the heating areas A 2 , A 3 , which have different surface layer thicknesses.
  • the fixing control temperatures TGT i of A 4 and A 5 are controlled at the same temperature. Therefore, the fixing performance of the heating areas A 1 , A 6 and A 7 with little surface wear is not a problem, but is supplied in the heating areas A 2 , A 3 , A 4 and A 5 where the surface wear is large and the surface is thin. Excess heat.
  • the fixing nip width may be large, which may cause high temperature offset.
  • the fixing control temperature TGT i is corrected corresponding to the increase of the width of the fixing nip N. Furthermore, in addition to this, a correction that reduces the calorific value of the heat generation blocks HB 2 , HB 3 , HB 4 , and HB 5 corresponding to the heating areas A 2 , A 3 , A 4 , and A 5 where the surface film of the fixing film 202 is highly worn. Add Thus, the occurrence of high temperature offset can be suppressed.
  • correction is performed to reduce the amount of heat generation of the heat generation block HB i of the heating area A i corresponding to the end of the recording material P.
  • the amount of heat supplied is appropriate, and the curling phenomenon can be suppressed.
  • the correction of the fixing control temperature suitable for the change of the physical properties of the fixing film 208 and the pressure roller 208 generated according to the use condition of the user is executed.
  • an image heating apparatus can be obtained that can always obtain stable fixing performance regardless of the use conditions of the user. That is, in an image heating apparatus using a heating source that controls heat generation of a plurality of heating elements according to image information, depending on the use conditions of the user, a difference in physical properties occurs in the longitudinal direction of each member forming the image heating apparatus There is.
  • the amount of heat supplied to the recording material and the toner can be controlled in the longitudinal direction by controlling the calorific value of the plurality of heating elements independently in accordance with the difference in the physical properties generated in the longitudinal direction. It becomes possible to be constant regardless of the difference. Therefore, according to this embodiment, it is possible to provide an image heating apparatus capable of obtaining stable fixing performance regardless of the use condition of the user.
  • the cumulative heat generation amount of each heat generation block HB i is defined as the product of the control target temperature at the time of execution of the fixing heating operation and the passing time of the recording material.
  • the product of the amount of power supplied to each heating element and the passing time of the recording material may be accumulated and acquired.
  • Example 2 A second embodiment of the present invention will be described.
  • Example 2 relates to control of suppressing abrasion of the surface layer of the fixing film 202 corresponding to the heating area A i where the accumulated heat generation amount is increased, as an application example of Example 1.
  • the same reference numerals as in the first embodiment denote the same parts in the second embodiment, and a description thereof will not be repeated. Matters not particularly described in the second embodiment are the same as in the first embodiment.
  • the PFA resin layer on the surface of the fixing film 202 corresponding to the heat generation block HBi (multiple) whose accumulated heat generation amount has increased is thinner.
  • the PFA resin layer corresponding to the heat generation block HBi (small) having a small accumulated heat generation value is less worn and is thicker than the PFA resin layer of the heat generation block HBi (multiple) .
  • the heat capacity of the PFA resin layer is also different. If the heat capacity of the PFA resin layer of the fixing film 202 is different, the following problems may occur.
  • the time required to raise the surface temperature of the fixing film 202 to 180 ° C. which is a fixable temperature, differs.
  • the time required for the temperature rise is shorter for the heat generating block HB i ( more ) in which the PFA resin layer is thinner than for the heat generating block HB i ( less ) in which the PFA resin layer remains thick.
  • current supply to the heating block HB i heater 300 is intended to be started at the same time at a predetermined timing.
  • the heat generation block HB i (more) and the heat generation block HB i ( less ) are simultaneously energized, the heat generation block HB i ( more ) has the surface temperature of the fixing film 202 than the heat generation block HB i ( less ). It will reach 180 [° C] quickly.
  • the result of observing the surface temperature of the fixing film 202 is shown in FIG.
  • the power control of the heat generation block HB i (multiple) that has reached the target temperature earlier is the fixing control temperature targeted by the detection temperature of the thermistor TH (low) located in the heat generation block HB (small). It will be continued until TGT i is reached. Therefore, the heat storage amount of the portion including the portion of the pressure roller 208 corresponding to the heat generating block HB i (multiple) increases. As a result, in the portion corresponding to the heat generating block HBi (multiple) , it becomes disadvantageous for the occurrence of high temperature offset due to the excess of the heat supply and the wear of the PFA resin layer.
  • the difference between the heating block HB (multi) which PFA resin layer of the fixing film 202 is presumed to thin, thick and heat block HB inferred (small) is arbitrarily set in the fixing device 200 If the value exceeds the predetermined value, the following control is performed. That is, the amount of supplied heat is delayed by delaying the start timing of energization to the heat generation block HB i (multiple) than the heat generation block HB i (small) and reducing the timing at which each heat generation block reaches a predetermined target temperature. Control to make it appropriate.
  • the count value CAFi of the cumulative heat generation of the first embodiment is used to determine the energization start timing, the determination may be made using a value indicating a cumulative heat generation amount defined separately. By this control, the excess amount of heat supply is suppressed, and the avoidance of high temperature offset and the reduction of wear of the PFA resin layer are realized.
  • the energization start timing of the heat generation block HB i (multiple) is delayed with respect to the energization start timing of the heat generation block HB (small) .
  • the heat generation block HB i (more ) Is delayed in accordance with Table 6. (Table 6)
  • the energization start timing of the heat generation block HB (multiple) is delayed by 0.4 [seconds] from the heat generation block HB (small) which is energized at the energization start timing which is the reference of the fixing device 200.
  • the delay time of the energization start timing should be determined in consideration of the configuration of the fixing device 200, and is not limited to the numerical values in Table 6.
  • Example 2 The result of having verified the effect of Example 2 which enforces the above control is shown.
  • the same image pattern (FIG. 12A) as that described in Example 1 is repeated on A4 size recording material P for three sheets continuously, on standby, and three sheets are continuously repeated.
  • the fixing device 200 used As the fixing film 202 in which surface layer wear has progressed, the fixing film 200 used is one obtained by passing up to 100,000 sheets in the description of the first embodiment.
  • the count value CAF 2 to 5 of the heat generation block HB 2 to 5 which is the heat generation block HB (multiple) is 25956, and the heat generation block HB (small) HB 1 having a small cumulative heat value, the count value CAF 1 of HB 6 to 7 , CAF 6 ⁇ 7 are each 20736.
  • the difference is 5220.
  • the delay time of the energization start timing at the difference 5220 of the count value CAFi is 0.4 seconds in accordance with Table 6, and delays the energization start timing to the heat generation blocks HB 2 to 5 by 0.4 seconds.
  • the timing when the surface temperature of the fixing film 202 reaches 180 [° C.] at which the fixing film 202 can be fixed is delayed by the heat generation block HB by delaying the timing for starting the energization of the heat generation block HB (multiple) . It becomes the same in (f) and heat generation block HB (f) . That is, it is possible to make the heat storage amount at the position corresponding to the heat generation block HB (multiple) proper.
  • the result of having confirmed abrasion of PFA resin layer in FIG. 16 is shown.
  • the horizontal axis of the graph represents the number of sheets of the recording material P (sheets), and the vertical axis represents the surface layer thickness of the fixing film 202.
  • the amount of abrasion of the PFA resin layer of 100000 sheets or less is reduced compared to the one controlled by the energization start timing of the comparative example after 100000 sheets according to the control in the second embodiment. I was able to confirm that it was done.
  • control is performed to delay the current application start timing to the heat generation block HB (multiple) , but the surface temperature of the fixing film 202 is increased to 180 ° C. at which fixing ability can be obtained as shown in FIG. It was confirmed that there was no problem with fixability because it was done.
  • the second embodiment has been described as suppressing high temperature offset even when a difference occurs in the surface film thickness of the fixing film 202, but various kinds of recording materials P used in the image forming apparatus 100 are used.
  • a recording material P referred to as glossy paper which can provide an image quality equivalent to that of a photo.
  • the image quality of glossy paper is influenced by the state of the fixing device 200, and temperature unevenness on the surface of the fixing film 202 may affect the uniformity of gloss of a fixed toner image.
  • the following can be considered as an application example of the second embodiment.
  • the surface temperature of the fixing film 202 becomes a fixable temperature
  • the surface temperature is surely equalized to a uniform temperature by not conveying the immediate recording material P to the fixing nip but by delaying the conveyance timing.
  • Example 2 in accordance with the surface wear of the fixing film 202, for adjusting the energization start timing of each heating block HB i.
  • Example 3 A third embodiment of the present invention will be described. As described in the first embodiment, the change in hardness of the pressure roller 208 associated with sheet passing becomes large at the beginning. When a large number of similar patterns are passed under the conditions, the hardness of the elastic layer locally decreases in the longitudinal direction of the pressure roller 208, and the fixing nip N becomes uneven in the longitudinal direction of the pressure roller I will.
  • the third embodiment in order to take measures against this, the difference in hardness between the heat generating block having a large heat generation history and the pressure roller 208 located in a small heat generating block is suppressed. Thereby, stable conveyance of the recording material P is realized.
  • Example 1 For Example 1, first, a correction term TAR cumulative heating history information from the accumulated rotation time Tsum, calculates the correction term TAF i of cumulative heat generation history information from the cumulative amount of heat generated. Then, by performing the correction of the heating value of each heating block HB i from the calculation result, thereby suppressing partial reduction in the hardness of the pressure roller 208.
  • the correction of the amount of heat generation suppresses the partial hardness reduction of the pressure roller 208
  • the difference in hardness between the pressure roller 208 of the heat generation block having many heat generation history and the heat generation block having less heat generation history is reduced. It is not possible.
  • the partial hardness difference in the longitudinal direction of the pressure roller 208 is greater than or equal to the predetermined hardness difference, the following occurs.
  • the center of the fixing nip N is slightly thinner than the end in the longitudinal direction, and the recording material nipped and conveyed by the fixing nip N is used.
  • the heater in which the heating element is divided controls each heating element independently, a partial hardness reduction of the pressure roller occurs, and as a result, the fixing nip as shown in FIG. 17A. There is also a possibility that the shape of N can not be maintained.
  • the fixing nip N has a center portion thicker than the end portion.
  • the speed of the recording material P nipped and conveyed in such a shape of the fixing nip N is faster at the central portion than at the longitudinal end, and the force for moving the recording material P to the longitudinal central portion acts to perform recording. Wrinkles occur on the material P.
  • the amount of heat generated by the heat generation blocks HB 1 and HB 2 at the longitudinal end (hereinafter referred to as the image side end) of the toner image exists. Become more.
  • the hardness reduction amount of the image side end of the pressure roller is the opposite longitudinal end where the image does not exist with the heat generation blocks HB 3 , HB 4 and HB 5 at the central part (hereinafter, the image side end).
  • the heat generation block HB 6 becomes larger than HB 7 .
  • the width of the fixing nip N is such that the image side end> the image side end> the center, and the fixing nip N becomes uneven in length.
  • the speed of the recording material P nipped and conveyed by the fixing nip N is higher at the image side end than at the opposite image side end, and the recording material P is twisted in the fixing nip. .
  • the trailing edge of the image side end portion of the recording material P moves to the end when the recording material P passes the transfer nip.
  • the film jumps to the fixing film 202 side.
  • the recording material P on which the toner image is formed is conveyed to the fixing nip N in a one-loop state twisted with respect to the fixing nip N, and thus rubs against the fixing film 202 and the unfixed toner image is disturbed.
  • the "image rubbing" phenomenon occurs by fixing as it is.
  • the image patterns (A) and (B) of FIG. 18 are formed on the A4 size recording material P, and 350,000 sheets are continuously passed while the stop state is repeated 150000 sheets.
  • the endurance test was done.
  • the width of the fixing nip N and the hardness of the pressure roller 208 were measured.
  • 50 sheets of the recording material P left to stand in a high temperature and humidity environment of 30 ° C./80% for 2 days are continuously fed as a condition where wrinkles of the recording material P are easily generated. P wrinkles, image rubbing was confirmed.
  • the hardness of the pressure roller 208 is an Asker-C hardness meter (weight of 9.8 N, taken as an average value of measurement values obtained by measuring four circumferential positions of the pressure roller 208 located in each heating block HB i ) It is a measured value in In the method of measuring the width of the fixing nip N, first, the recording material P having a toner image on the entire surface is passed with the pressure roller 208 facing, and the sheet is nipped and conveyed by the fixing nip N. Pass the paper to the left and leave a gloss mark of the fixing nip N on the recording material.
  • the hardness reduction of the central portion in the longitudinal direction of the pressure roller 208 located in the heat generating blocks HB 3 , HB 4 and HB 5 is smaller than that of the end portion. large. Therefore, the width of the fixing nip N also increases in the central part in the longitudinal direction, and the shape of the fixing nip N becomes thicker in the central part than at the end, and becomes an uneven fixing nip N in the longitudinal direction. I understand that it is going. As described above, in the fixing nip N in which the center portion is thicker and uneven than the end portion, the transportability of the recording material P becomes unstable, and therefore the recording material P wrinkles.
  • each of the heat generation blocks HB 1 and HB 2 at the longitudinal end and the heat generation blocks HB 6 and HB 7 at the longitudinal end opposite to the HB 2 and the heat generation blocks HB 3 , HB 4 and HB 5 at the longitudinal center The average value of the hardness of the pressure roller 208 is calculated corresponding to the position of. Furthermore, the average value of the width of the fixing nip N is also calculated. The average fixing nip N width when the width of the fixing nip N at the center is subtracted from the width of the fixing nip N at the end, and the hardness of the fixing nip N at the center from the calculated hardness of the fixing nip N at the end. The average pressure roller 208 hardness is calculated when.
  • Table 9 The results and the occurrence of recording material P wrinkles and image rubbing are summarized in Table 9. In the table, "o" indicates that there is no problem in the transportability of the recording material P, and that the recording material P wrinkles and the image rubbing are not generated.
  • the third embodiment controls the amount of heat generation of the divided heat generation block so as to maintain the shape of the fixing nip N as a thin shape at the central portion compared with the longitudinal end, and thereby the recording material P wrinkles and the image rubbing. This realizes a stable transportability of the recording material P which does not occur.
  • Control method for realizing the transport of the stable recording material P first, obtains the correction value from the sum of the correction term TAF i correction term TAR and cumulative heat generation history information of the cumulative heat generation history information of each of the heating blocks HB i.
  • the method of heat generation of the heat generation block HBi (small amount) with a small heat generation history is controlled by the value calculated from the difference between the maximum value and the minimum value between the heat generation blocks of the correction value, and the difference of the heat generation history is reduced.
  • Table 9 The result of having summarized the result of Table 9 and the maximum difference of the correction value between each exothermic block is shown in Table 10.
  • Regard correction term TAR correction term TAF i uses a calculation method described in Example 1.
  • the difference between the correction value of the heat generation block HB i (large) with many heat generation histories and the heat generation block HB i (small) with small heat generation histories which is the maximum difference between correction values
  • the difference between the correction values can be suppressed to 2 or less by performing control to increase the accumulated heat generation amount of the heat generation block HBi (small) of the present embodiment.
  • the control of the third embodiment will be described with reference to the flowchart of FIG.
  • the sum of the correction term TAR of each heat generation block HB i and the correction value of the correction term TAF i is calculated, and when the difference between the heat generation block HB i is 2 or less, the process moves to S2001 and the control similar to that of the first embodiment Do. If the difference between the heat generating blocks HB i is larger than 2, the process shifts to S2002 (S2000). Less heat generation history heating block HB i determines whether or not the recording material P passes through the (small) (S2002), if not pass classifies the heating area A i in the non-paper passing heated area AN (S2006).
  • the recording material P passes the heat generation block HBi (small) with a small heat generation history, it is determined whether the image range passes the heat generation block HBi (small) (S2003).
  • Heating block HB i (small) a case where the image range passes the heating block HB i (small) and classify image heating area AI (S2004), if not pass the heating block HB i (small) non-image heating area AP And (S2005).
  • control is performed to increase the heat generation history of the heat generation block HB i (small) having a small heat generation history.
  • the temperature of the heat generation block HBi small amount
  • heat may be transmitted to the fixing film 202 of the image heating area AI having a toner image, whereby high temperature offset may occur.
  • the fixing control temperature TGT i of the non-image heating area AP is set to 230 ° C. (S2008).
  • Example 3 which implements the above control is shown.
  • the image pattern shown in FIG. 12A is formed on the recording material P of A4 size using the image forming apparatus 200 described in the first embodiment, and three sheets are continuously fed and stopped while repeating up to 150,000 sheets. The endurance test was done. Then, the width of the fixing nip N and the hardness of the pressure roller 208 were measured. By doing so, heating block HB 3 , HB 4 , HB 5 at the center of the center, heating block HB 1 , HB 2 near the longitudinal end, heating block HB 6 near the longitudinal end on the opposite side, HB 7 respectively. The average hardness of the corresponding pressure roller and the average fixing nip width were measured.
  • Example 1 is used as a comparative example, and the respective results are shown in Table 11.
  • "o" indicates that there is no problem in the transportability of the recording material P, and that the recording material P wrinkles and the image rubbing are not generated.
  • Example 1 when the width of the fixing nip N when passing 150,000 sheets is compared, the fixing nip N becomes thicker at the center compared to the longitudinal end of the fixing nip N, and the recording material P wrinkles It has occurred.
  • Example 3 the calorific value of the heat generation blocks HB 1 , HB 2 , HB 6 and HB 7 having a small heat generation history is increased to reduce the difference between the heat generation blocks HB 3 , HB 4 and HB 5 having a large heat generation history. By setting the value to a predetermined value or less, the occurrence of the recording material P wrinkles could be suppressed.
  • the generation of the wrinkles of the recording material P is a problem, but depending on the state of the hardness of the pressure roller 208, the following cases may be made.
  • the image pattern of FIG. 18B is passed such that the hardness of the longitudinal end of the pressure roller 208 decreases, the hardness of the pressure roller of the image side end of the pressure roller 208 decreases, and the pressure roller The conveying force near the longitudinal end of 208 is significantly higher than that at the center. Then, it is conceivable that a single loop may occur in the recording material P discharged to the outside of the image forming apparatus 100.
  • Example 1 when passing 150000 sheets, the nip width is such that the image side end portion is thicker than the central portion of the fixing nip N.
  • Example 3 the calorific value of the heat generation blocks HB 3 , HB 4 , HB 5 , HB 6 , and HB 7 having a small heat generation history is increased to reduce the difference between the heat generation blocks HB 1 and HB 2 having a large heat generation history.
  • the occurrence of image rubbing of the recording material P can be suppressed.
  • the third embodiment by performing the correction of the fixing control temperature suitable for the change in the hardness of the pressure roller 208 caused by the use condition of the user, the conveyance performance is always stable regardless of the use condition of the user.
  • the image heating device can be
  • 200 fixing device
  • 202 fixing film
  • 208 pressure roller
  • 300 heater
  • 305 substrate
  • 302a, 302b heating element
  • thermistor 400 ...
  • Control circuit HB1 to HB7 ... Heat generation block

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Fixing For Electrophotography (AREA)

Abstract

La présente invention comprend un dispositif de fixation (200) comprenant un dispositif de chauffage (300) apte à chauffer sélectivement une pluralité de blocs de génération de chaleur distribués le long de la direction longitudinale d'un substrat (305), et est caractérisé en ce qu'il comprend une unité de commande de courant électrique (400) qui obtient les quantités cumulatives de chaleur générées dans une pluralité de zones de génération de chaleur, le temps de rotation cumulatif d'un rouleau de pressurisation (208), et des informations concernant un matériau d'enregistrement qui passe à travers une partie de pincement de fixation, et, sur la base des informations obtenues, commande le courant électrique des corps de génération de chaleur (302a, 302b).
PCT/JP2018/029100 2017-08-04 2018-08-02 Dispositif de chauffage d'image et dispositif de formation d'image WO2019027012A1 (fr)

Priority Applications (1)

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JP2017-151516 2017-08-04
JP2017151516 2017-08-04
JP2018-141516 2018-07-27
JP2018141516A JP7073220B2 (ja) 2017-08-04 2018-07-27 像加熱装置及び画像形成装置

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20110091251A1 (en) * 2009-10-20 2011-04-21 Samsung Electronics Co., Ltd Heating roller having resistive heating element and fusing device including heating roller
JP2014178668A (ja) * 2013-02-14 2014-09-25 Ricoh Co Ltd 定着装置及び画像形成装置
JP2014228677A (ja) * 2013-05-22 2014-12-08 株式会社リコー 画像形成装置
JP2015045672A (ja) * 2013-08-27 2015-03-12 株式会社リコー 定着装置、画像形成装置、定着制御方法及び定着制御プログラム
JP2015176010A (ja) * 2014-03-17 2015-10-05 株式会社リコー 定着制御装置、定着制御方法及び画像形成装置

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20110091251A1 (en) * 2009-10-20 2011-04-21 Samsung Electronics Co., Ltd Heating roller having resistive heating element and fusing device including heating roller
JP2014178668A (ja) * 2013-02-14 2014-09-25 Ricoh Co Ltd 定着装置及び画像形成装置
JP2014228677A (ja) * 2013-05-22 2014-12-08 株式会社リコー 画像形成装置
JP2015045672A (ja) * 2013-08-27 2015-03-12 株式会社リコー 定着装置、画像形成装置、定着制御方法及び定着制御プログラム
JP2015176010A (ja) * 2014-03-17 2015-10-05 株式会社リコー 定着制御装置、定着制御方法及び画像形成装置

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